Please update the title to indicate that this was written in 2009. In the meanwhile, Haskell has gained (besides Happstack) two excellent web frameworks: Snap and Yesod.
One of the points of critique has been addressed now is database access. For instance, Persistent provides type-safe database access:
The author also mentions the problem that exceptions can only be caught in the IO monad. But this has become less of a problem, since more people started using monad transformers (such as ErrorT) to add error handling to their monads. ErrorT allows you to catch exceptions within that monad. For instance, quoting from one of my own projects:
readEntry :: MonadIO m => Corpus -> String -> ErrorT CorpusError m Text
readEntry is a function that takes a Corpus and a String, and returns Text in a monad of the class MonadIO if the function is successful. Otherwise it reports errors in the form of a CorpusError. You could now, for instance, run this function with runErrorT, and it will return an ordinary Either value in the given monad (Left CorpusError in the case of an error, Right Text when the call is successful).
As someone who's learning Haskell, I read the post because I'm interested in the language's capabilities in the web arena. But your site itself is brilliant! You are really on to something with vocabulink.com. I've formally studied 10 human languages, of which I can speak/write/read 3 fluently, and have passive understanding of another 2-3. People often ask me how I learn languages, and a good part of my answer is very similar to what you are doing with vocabulink. As you've discovered, the key is to use vivid, even silly, mnemonic devices. Building up a large vocabulary is key to learning a language. Don't waste your money on flashy tools like Rosetta Stone -- they don't work for most people above the age of 8 or 10. Adults learn differently than children.
So if someone out there is looking to learn a foreign language, my recommendation is to combine vocabulink's approach to build up a large vocabulary, and find the best concise grammar available for your target language. If you don't remember grammar fundamentals (e.g., what's a prepositional phrase, direct object, relative pronoun, etc.), then you need to find a good book in your native language to review those concepts.
In any case, cool concept for a web site. Sorry for the off-topic post. Thanks for telling us about your experiences with Haskell. I do think that Haskell web capabilities have come a long way since 2009, particularly Yesod (I'm not familiar with Snap).
How secure are these Haskell web frameworks? (snap, happstack, etc.). Without a django and rails level of exposure, presumably they have quite a few holes still?
I don't know about their maturity, but I think Haskell's type system and purity would help with security.
It doesn't have anything like `eval` and is much less tolerant of weird input by default than dynamically typed languages (at least in my experience). Having no or limited state also helps--bad input and other mistakes tend to be more localized when they can't possibly change anything else in the program.
If you're really crazy about security, then I suspect the Haskell code would also be much easier to analyze and verify.
Well, one feature that Yesod has really been focused on are type-safe URLs[1]. I imagine this would provide some level of security benefit as the framework knows "Ah, in this GET request we should have a Date, an Integer, a UserID, etc".
The implementation may still have bugs, I suppose, but you can be sure that it's at least being heavily thought about.
I imagine forms may work the same way, though I'm not sure about that.
That's not how security works. FreeBSD has more exposure than OpenBSD, but OpenBSD is more secure. Security isn't a measure of how many people have heard of your project, it is a question of whether or not you have carefully designed your project to be secure. Haskell helps prevent a ton of errors that can cause security holes. On top of that, yesod at least has been very carefully designed to both be secure itself, and to make applications developed in yesod be secure by default.
Security holes don't just magically go away when software gets popular. You should be striving to not create security holes in the first place.
I've been wondering how well-suited FRP (implemented either in Haskell or something else) is for back-end technology. It seems like it might be overkill, but it does have a certain conceptual elegance to it.
Coding in Haskell is not like coding in a more imperative language like Python or Java. Haskell is incredibly terse, and most of the work is done in your mind, trying to figure out exactly how best to declare what you're trying to achieve.
Once the thinking part is complete you can usually express what you're trying to do in less than ten lines.
[+] [-] microtonal|14 years ago|reply
One of the points of critique has been addressed now is database access. For instance, Persistent provides type-safe database access:
http://www.yesodweb.com/book/persistent
The author also mentions the problem that exceptions can only be caught in the IO monad. But this has become less of a problem, since more people started using monad transformers (such as ErrorT) to add error handling to their monads. ErrorT allows you to catch exceptions within that monad. For instance, quoting from one of my own projects:
readEntry is a function that takes a Corpus and a String, and returns Text in a monad of the class MonadIO if the function is successful. Otherwise it reports errors in the form of a CorpusError. You could now, for instance, run this function with runErrorT, and it will return an ordinary Either value in the given monad (Left CorpusError in the case of an error, Right Text when the call is successful).[+] [-] ps8ed|14 years ago|reply
[+] [-] jnbiche|14 years ago|reply
So if someone out there is looking to learn a foreign language, my recommendation is to combine vocabulink's approach to build up a large vocabulary, and find the best concise grammar available for your target language. If you don't remember grammar fundamentals (e.g., what's a prepositional phrase, direct object, relative pronoun, etc.), then you need to find a good book in your native language to review those concepts.
In any case, cool concept for a web site. Sorry for the off-topic post. Thanks for telling us about your experiences with Haskell. I do think that Haskell web capabilities have come a long way since 2009, particularly Yesod (I'm not familiar with Snap).
[+] [-] sp00nman|14 years ago|reply
[+] [-] tikhonj|14 years ago|reply
It doesn't have anything like `eval` and is much less tolerant of weird input by default than dynamically typed languages (at least in my experience). Having no or limited state also helps--bad input and other mistakes tend to be more localized when they can't possibly change anything else in the program.
If you're really crazy about security, then I suspect the Haskell code would also be much easier to analyze and verify.
[+] [-] losvedir|14 years ago|reply
The implementation may still have bugs, I suppose, but you can be sure that it's at least being heavily thought about.
I imagine forms may work the same way, though I'm not sure about that.
[1] http://www.yesodweb.com/home/snoyberg/blogs/2011/08/shakespe...
[+] [-] SomeOtherGuy|14 years ago|reply
Security holes don't just magically go away when software gets popular. You should be striving to not create security holes in the first place.
[+] [-] scarmig|14 years ago|reply
Anyone play around with this idea?
[+] [-] davorak|14 years ago|reply
Recent reddit conversation: http://www.reddit.com/r/haskell/comments/mwbvj/elm_functiona...
[+] [-] dustingetz|14 years ago|reply
[1] http://jekor.com/vocabulink/vocabulink.pdf
[+] [-] dowskitest|14 years ago|reply
[+] [-] savoy11|14 years ago|reply
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[+] [-] unknown|14 years ago|reply
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[+] [-] unknown|14 years ago|reply
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[+] [-] joe_fishfish|14 years ago|reply
Once the thinking part is complete you can usually express what you're trying to do in less than ten lines.
[+] [-] steeleduncan|14 years ago|reply
Besides, 2500 lines of Haskell is likely to be far more functional than 2500 lines of PHP.